Lubricant additive composition, lubricating composition containing same and engine oil composition consisting of lubricating composition

ABSTRACT

A lubricant additive composition including, as a component (A), an organic molybdenum compound represented by general formula (1) described in the specification, and as a component (B), an amine compound represented by general formula (2) described in the specification, wherein content of the component (B) is 1 to 20 parts by mass relative to 100 parts by mass of molybdenum atoms of the component (A), and a lubricating composition containing same.

TECHNICAL FIELD

The present invention relates to a lubricant additive compositioncontaining an organic molybdenum compound, a lubricating compositioncontaining the lubricant additive composition and an engine oilconsisting of the lubricating composition.

BACKGROUND ART

Reductions in automobile fuel consumption initiated due to the oilcrisis is a very important issue in view of resource protection andenvironmental protection. Automotive fuel consumption has been improvedby reduction of the body weight of automobiles, improvements in enginecombustion and reduction of friction in engines and power trains. Enginefriction has been reduced by, for example, improvement in valve systemmechanisms, reduction of surface roughness of sliding members and use offuel-efficient engine oil. In order to reduce fuel consumption by engineoil, reduction of viscosity aimed at reducing friction loss under fluidlubrication conditions in piston systems and bearing members has beenstudied, and addition of friction reducing agents aimed at reducingfriction loss under mixed lubrication and boundary lubrication in valvesystems have been proposed.

Organic molybdenum compounds containing sulphur such as molybdenumdialkyldithiocarbamate and molybdenum dialkyldithiophosphate have theexcellent effect of friction reduction, and thus are widely used forengine lubricating oil and the like. However, the effect of frictionreduction only by increasing the amount of organic molybdenum compoundsadded has limitations, and an increase in the amount of organicmolybdenum compounds added causes problems such as generation ofdeposits due to precipitated or deteriorated organic molybdenumcompounds. In order to improve the effect of the organic molybdenumcompound, use of lubricating oil compositions containing an organicmolybdenum compound and an ashless friction regulator, for examplelubricating oil compositions containing an organic molybdenum compoundand a polyhydric alcohol fatty acid partial ester (for example, seePatent Documents 1 to 3) or an alkyl alkanolamine or fatty acidalkanolamide (for example, see Patent Documents 4 and 5) have beenstudied.

It is believed that organic molybdenum compounds containing sulphur aredecomposed on sliding surfaces to form films similar to molybdenumdisulphide, which films reduce friction. Therefore, lubricating oilcompositions (for example, see Patent Documents 6 and 7) containing anorganic molybdenum compound containing sulphur and tetrabenzyl thiuramdisulphide have been studied and it is thought that in order to increasesolubility of tetrabenzyl thiuram disulphide, an amine compound iseffective (for example, see Patent Document 7). However, in order todissolve tetrabenzyl thiuram disulphide in abase oil, a high amount ofamine compound is required and copper components of machines made ofcopper or copper alloys are corroded in some cases.

CITATION LIST Patent Documents

[Patent Document 1] Japanese Patent Application Publication No.H05-279686

[Patent Document 2] Japanese Patent Application Publication No.H08-067890

[Patent Document 3] Japanese Patent Application Publication No.2005-082709

[Patent Document 4] Japanese Patent Application Publication No.H07-150173

[Patent Document 5] Japanese Patent Application Publication No.2003-221588

[Patent Document 6] Japanese Patent Application Publication No.2012-197393

[Patent Document 7] Japanese Patent Application Publication No.2013-119597

SUMMARY OF INVENTION Technical Problem

The level of reduction in automobile fuel consumption being sought hasrecently increased, and there is a need for an engine oil having furtherreduced friction. In addition, a lubricant having an improved effect offriction reduction for other machines is also expected. Therefore, anissue to be addressed by the present invention is to further improve theeffect of friction reduction by an organic molybdenum compound.

Solution to Problem

The inventors of the present invention carried out extensive studies inorder to solve the above problem and, as a result, found that by addinga small amount of dialkylamine to an organic molybdenum compoundcontaining sulphur, the effect of friction reduction by the organicmolybdenum compound is increased without corrosion of copper or copperalloys. The inventors thereby completed the present invention. Namely,the present invention pertains to a lubricant additive compositioncontaining, as a component (A), an organic molybdenum compoundrepresented by the following general formula (1), and as a component(B), an amine compound represented by the following general formula (2),wherein content of the component (B) is 1 to 20 parts by mass relativeto 100 parts by mass of molybdenum atoms derived from the component (A):

wherein R¹ to R⁴ respectively represent an alkyl group having 1 to 18carbon atoms, and X¹ to X⁴ respectively represent an oxygen atom or asulphur atom;

wherein R⁵ and R⁶ respectively represent an alkyl group having 1 to 18carbon atoms or an alkenyl group having 2 to 18 carbon atoms.

Advantageous Effects of Invention

By adding to an organic molybdenum compound represented by generalformula (1) a dialkylamine represented by general formula (2) at aspecific ratio, the effect of friction reduction by the organicmolybdenum compound can be improved and corrosion of components used inmachines, particularly corrosion of copper and copper alloys can besignificantly prevented. Therefore, the present invention can provide anadvantageous lubricant additive composition for lubricatingcompositions.

DESCRIPTION OF EMBODIMENTS

In the lubricant additive composition of the present invention, thecomponent (A) is an organic molybdenum compound represented by generalformula (1). In the general formula (1), R¹ to R⁴ respectively representan alkyl group having 1 to 18 carbon atoms. Examples of the alkyl grouphaving 1 to 18 carbon atoms include a methyl group, an ethyl group, apropyl group, a butyl group, a pentyl group, a hexyl group, a heptylgroup, an octyl group, an isopropyl group, an isobutyl group, asecondary butyl group, a tertiary butyl group (hereinafter “tertiary” isabbreviated as “t”), an isopentyl group, a secondary pentyl group, at-pentyl group, a secondary hexyl group, a secondary heptyl group, asecondary octyl group, a 2-ethylhexyl group, a nonyl group, an isononylgroup, a decyl group, a branched decyl group, a dodecyl group, atridecyl group, a branched tridecyl group, a tetradecyl group, apentadecyl group, a hexadecyl group, a heptadecyl group, an octadecylgroup and the like. Because of preferable solubility to mineral oil andhydrocarbon synthetic oil and preferable thermal stability, R¹ to R⁴ arerespectively preferably an alkyl group having 6 to 16 carbon atoms andmore preferably an alkyl group having 7 to 14 carbon atoms. Branchedalkyl groups are preferred to linear alkyl groups because the molybdenumcompound may have a lower melting point and may be less deposited. R¹ toR⁴ may be the same hydrocarbon group or different hydrocarbon groups;however, it is preferable that at least one of R¹ to R⁴ is differentfrom other groups because the molybdenum compound may have a lowermelting point and may be less deposited, and it is more preferable thatR¹ and R² are the same and R³ and R⁴ are the same and R¹ and R³ aredifferent because of industrial availability. Specifically, the compoundwherein R¹ and R² are respectively 2-ethylhexyl and R³ and R⁴ arerespectively a branched tridecyl group, or R¹ to R⁴ are respectively2-ethylhexyl is preferable and a compound wherein R¹ and R² arerespectively 2-ethylhexyl and R³ and R⁴ are respectively a branchedtridecyl group is more preferable.

In general formula (1), X¹ to X⁴ respectively represent an oxygen atomor a sulphur atom. Because of excellent lubricity, it is preferable thattwo to three of X¹ to X⁴ are sulphur atoms and the rest are oxygenatom(s). For example, a compound wherein X¹ and X² are respectively asulphur atom and X³ and X⁴ are respectively an oxygen atom is preferred.

In the present invention, an organic molybdenum compound (A1) wherein R¹and R² are respectively 2-ethylhexyl and R³ and R⁴ are respectively abranched tridecyl group; and X¹ and X² are respectively a sulphur atomand X³ and X⁴ are respectively an oxygen atom, and an organic molybdenumcompound (A2) wherein R¹ to R⁴ are respectively 2-ethylhexyl; and X¹ andX² are respectively a sulphur atom and X³ and X⁴ are respectively anoxygen atom are preferred, and the organic molybdenum compound (A1) ismore preferred.

In the lubricant additive composition of the present invention, thecomponent (B) is an amine compound represented by general formula (2).In the general formula (2), R⁵ and R⁶ respectively represent an alkylgroup having 1 to 18 carbon atoms or an alkenyl group having 2 to 18carbon atoms. Examples of the alkyl group having 1 to 18 carbon atomsinclude alkyl groups exemplified for R¹ to R⁴ in the general formula(1). Examples of the alkenyl group having 2 to 18 carbon atoms include avinyl group, a 1-methylethenyl group, a 2-methylethenyl group, apropenyl group, a butenyl group, an isobutenyl group, a pentenyl group,a hexenyl group, a heptenyl group, an octenyl group, a decenyl group, apentadecenyl group, an octadecenyl group and the like. R⁵ and R⁶ maybethe same group or different groups; however, it is preferable that R⁵and R⁶ are the same group because of industrial availability.

In the general formula (2), the sum of the carbon atoms of R⁵ and R⁶ ispreferably at least 8 and more preferably at least 12 because when theamine compound has an extremely low boiling point, the amine compound inthe general formula (2) is volatilized and eliminated during use.

Among the amine compounds represented by general formula (2),dibutylamine, dipropylamine, dihexylamine, diheptylamine, dioctylamine,bis(2-ethylhexyl)amine, dinonylamine, diisononylamine, didecylamine,di-branched decylamine, didodecylamine, di-branched tridecylamine,ditetradecylamine, dihexadecylamine, dioctadecylamine are preferredbecause of industrial availability, bis(2-ethylhexyl)amine,dinonylamine, diisononylamine, didecylamine, di-branched decylamine,didodecylamine, di-branched tridecylamine are more preferred because ofan increased effect of friction reduction, and bis (2-ethylhexyl) amineand di-branched tridecylamine are still more preferred.

In the present invention, the content of the component (B) is 1 to 20parts by mass relative to 100 parts by mass of molybdenum atoms derivedfrom the component (A). When the content of the component (B) is lessthan 1 part by mass, the effect of lubricity may not be sufficient, andwhen the content is more than 20 parts by mass, corrosion of copper orcopper alloys may occur. The component (B) is preferably 2 to 19 partsby mass, more preferably 5 to 18 parts by mass and still more preferably10 to 17 parts by mass relative to 100 parts by mass of molybdenum atomsderived from the component (A).

The lubricant additive composition of the present invention may consistof the component (A) and the component (B). However, in view of handlingand convenience upon use of the additive composition of the presentinvention, the composition may be dissolved in a base oil or may be in apackage combined with other lubricating oil additives. When thelubricant additive composition of the present invention contains othercomponents, the content of the component (A) is preferably at least 1%by mass and more preferably at least 20% by mass relative to the wholeamount of the lubricant additive composition.

The lubricant additive composition of the present invention is added toa base oil or a base oil and a thickener to be used as, respectively, alubricating oil composition or a grease composition. In the presentinvention, the lubricating oil composition and the grease compositionare collectively referred to as a lubricating composition. Examples ofthe base oil include mineral oils such as paraffin mineral oils,naphthene mineral oils and purified mineral oils obtained by subjectingthe above to hydrogenation refining, solvent deasphalting, solventextraction, solvent dewaxing, hydrogenation dewaxing, contact dewaxing,hydrogenolysis, alkali distilling, sulphuric acid cleaning or white claytreatment; hydrocarbon synthetic oils such as poly-α-olefins,ethylene-α-olefin copolymers, polybutenes, GTL (Gas to liquids) baseoils, alkylbenzenes and alkylnaphthalenes; ether synthetic oils such aspolyphenyl ethers, alkyl-substituted diphenyl ethers and polyalkyleneglycols; ester synthetic oils such as polyol esters, dibasic acidesters, hindered esters and monoesters; phosphate ester synthetic oils,polysiloxane synthetic oils, and fluorinated hydrocarbon synthetic oils.The base oils may be used alone or as a mixture of two or more. The baseoil for which the lubricant additive composition of the presentinvention is used is preferably a mineral oil or a hydrocarbon syntheticoil and more preferably a paraffin purified mineral oil, a poly-α-olefinor a GTL base oil because the effect of lubricity improvement by thecomponent (A) may be easily obtained.

Examples of the thickener used with the lubricant additive compositionof the present invention for a grease include soap or complex soapthickeners, organic non-soap thickeners, inorganic non-soap thickenersand the like. A grease made of abase oil and a thickener and notcontaining other additives may be referred to as a base grease. Theconsistency of the grease for which the lubricant additive compositionof the present invention is used may vary according to the applicationof the grease and is not particularly limited. The consistency isgenerally about 100 to 500, and the content of the thickener isgenerally about 5 to 20 parts by mass relative to 100 parts by mass ofthe base oil.

Examples of the soap thickener includes soaps obtained by reaction ofhigher fatty acids such as lauric acid, myristic acid, palmitic acid,stearic acid, 12-hydroxystearic acid, arachic acid, behenic acid,zoomaric acid, oleic acid, linoleic acid, linolenic acid and ricinoleicacid and bases such as lithium, sodium, potassium, aluminium, barium andcalcium, and complex soap thickeners obtained by reaction of the fattyacids and the bases above and acetic acid, benzoic acid, sebacic acid,azelaic acid, phosphoric acid, boric acid or the like. Examples of theorganic non-soap thickener include terephtalate thickeners, ureathickeners, fluorine thickeners such as polytetrafluoroethylene andfluorinated ethylene-propylene copolymers and the like. Examples ofinorganic non-soap thickener include montmorillonite, bentonite, silicaaerogel, boron nitride and the like. Among the thickeners, ureathickeners are preferable because the effect of friction reduction bythe component (B) is increased. Examples of the urea thickener includemonourea compounds obtained by reaction of monoisocyanates andmonoamines, diurea compounds obtained by reaction of diisocyanates andmonoamines, urea urethane compounds obtained by reaction ofdiisocyanates, monoamines and monools, tetraurea compounds obtained byreaction of diisocyanates, diamines and monoisocyanates and the like.

In the lubricating composition of the present invention, an extremelylow content of the component (A) of the present invention may cause aninsufficient effect of friction reduction, and an extremely high amountof addition may cause sludge and corrosion. When the lubricatingcomposition of the present invention is a lubricating oil composition,the component (A) in terms of the amount of molybdenum atoms ispreferably 50 to 2000 ppm by mass, more preferably 70 to 1500 ppm bymass and still more preferably 80 to 1000 ppm by mass relative to thewhole amount of the lubricating composition. When the lubricatingcomposition of the present invention is a grease composition, the amountof the component (A) added in terms of the amount of molybdenum atoms ispreferably 100 ppm by mass to 5% by mass, more preferably 150 ppm bymass to 3% by mass and still more preferably 200 ppm by mass to 2% bymass relative to the grease and the like.

Generally, the lubricating composition may contain, if necessary, ametal-based cleaner, an ashless dispersant, an antioxidant, an oilinessagent, an anti-wear agent, an extreme pressure agent, a rust preventingagent, a metal deactivator, a viscosity index improver, a pour pointdepressant, a solid lubricant and the like.

[Metal-Based Cleaner]

Examples of the metal-based cleaner include alkaline earth metalsulphonates, alkaline earth metal phenates, alkaline earth metalphosphonates, alkaline earth metal salicylates, alkaline earth metalnaphthenates and the like, and examples of the alkaline earth metalinclude magnesium, calcium, barium and the like. The lubricatingcomposition of the present invention preferably contains, as a component(C), an alkaline earth metal salicylate because of an increased effectof friction reduction by the component (A) and calcium salicylate ispreferred among others.

Metal-based cleaners having a total base number (TBN) according to ASTMD2896 of 20 to 600 mgKOH/g are known. When the TBN is extremely low, ahigh amount of metal-based cleaner must be added, and when the TBN isextremely high, the lubricity of the component (A) may be adverselyaffected. Metal-based cleaners diluted with light lubricant base oil orthe like are generally marketed and are available. The TBN of themetal-based cleaner as used in the present invention is a TBN of purecomponent without a diluent such as light lubricant base oil. Thecomponent (C) has a TBN of preferably 50 to 500 mgKOH/g and morepreferably 100 to 450 mgKOH/g. Generally, a metal-based cleaner has anincreased TBN by including a carbonate salt of an alkaline earth metal,and the component (C) of the present invention may contain a borate saltinstead of some of the carbonate salt.

When the content of the component (C) is extremely low, an effect by thecomponent (C) may not be sufficiently obtained, and when the content isextremely high, the effect of friction reduction by the component (A)may be decreased. Therefore, the content of the component (C) in thelubricating composition of the present invention is preferably 0.1% to10% by mass, more preferably 0.5% to 8% by mass and still morepreferably 1% to 5% by mass relative to the whole amount of thelubricating composition.

[Ashless Dispersant]

Examples of the ashless dispersant include succinimide dispersantsobtained by condensation reaction of alkenyl succinic anhydrides andpolyamine compounds, succinate ester dispersants obtained bycondensation reaction of alkenyl succinic anhydrides and polyolcompounds, succinate ester amide dispersants obtained by condensationreaction of alkenyl succinic anhydrides and alkanolamines, Mannich basedispersants obtained by condensation of alkylphenols and polyamines withformaldehyde, and the like. The lubricating composition of the presentinvention preferably contains, as a component (D), a succinimidedispersant because of an increased effect of friction reduction by thecomponent (A). Succinimide dispersants may be divided intomono-succinimide dispersants having one alkenyl succinimide group in amolecule and bis-succinimide dispersants having two alkenyl succinimidegroups, and bis-succinimide dispersants are preferred because ofexcellent effect of lubricity improvement. Ashless dispersants includeboric acid-modified ashless dispersants (compounds obtained bydehydration condensation of boric acid with ashless dispersants), andsuccinimide dispersants containing 0.1% to 5% by mass of boric acid asboron atoms are particularly preferred because of an increased effect offriction reduction by the component (A).

When the content of the component (D) in the lubricating composition ofthe present invention is extremely low, an effect by the component (D)may not be sufficiently obtained, and when the content is extremelyhigh, an effect corresponding to the added amount may not be obtainedand flowability may decrease. Therefore, the content of the component(D) is preferably 0.5% to 10% by mass, more preferably 1% to 8% by massand still more preferably 2% to 6% by mass relative to the whole amountof the lubricating composition.

[Antioxidant]

Examples of the antioxidant include aromatic amine antioxidants,phenolic antioxidants, phosphite ester antioxidants, thioetherantioxidants and the like. The lubricating composition of the presentinvention preferably contains, as a component (E), a phenolicantioxidant because the phenolic antioxidant has a high antioxidanteffect and an effect of lubricity improvement by the component (A) maycontinue over a long period.

Examples of the phenolic antioxidant includes phenolic antioxidantswithout ester group such as 2,6-di-t-butylphenol2,6-di-t-butyl-p-cresol, 2,6-di-t-butyl-4-methylphenol,2,6-di-t-butyl-4-ethylphenol, 2,4-dimethyl-6-t-butylphenol,4,4′-methylenebis(2,6-di-t-butylphenol), 4,4′-bis(2,6-di-t-butylphenol),4,4′-bis(2-methyl-6-t-butylphenol),2,2′-methylenebis(4-methyl-6-t-butylphenol),2,2′-methylenebis(4-ethyl-6-t-butylphenol),4,4′-butylidenebis(3-methyl-6-t-butylphenol),4,4′-isopropylidenebis(2,6-di-t-butylphenol),2,2′-methylenebis(4-methyl-6-cyclohexylphenol),2,2′-methylenebis(4-methyl-6-nonylphenol),2,2′-isobutylidenebis(4,6-dimethylphenol),2,6-bis(2′-hydroxy-3′-t-butyl-5′-methylbenzyl)-4-methylphenol,3-t-butyl-4-hydroxyanisole, 2-t-butyl-4-hydroxyanisole,4,4′-thiobis(3-methyl-6-t-butylphenol),4,4′-thiobis(2-methyl-6-t-butylphenol),2,2′-thiobis(4-methyl-6-t-butylphenol),2,6-di-t-butyl-α-dimethylamino-p-cresol,2,6-di-t-butyl-4-(N,N′-dimethylaminomethylphenol),bis(3,5-di-t-butyl-4-hydroxybenzyl)sulphide,tris{(3,5-di-t-butyl-4-hydroxyphenyl)propionyl-oxyethyl}isocya nurate,tris(3,5-di-t-butyl-4-hydroxyphenyl)isocyanurate,1,3,5-tris(3,5-di-t-butyl-4-hydroxybenzyl)isocyanurate,bis{2-methyl-4-(3-n-alkylthiopropionyloxy)-5-t-butylphenyl}sul phide,1,3,5-tris(4-t-butyl-3-hydroxy-2,6-dimethylbenzyl)isocyanurate,tetraphthaloyl-di(2,6-dimethyl-4-t-butyl-3-hydroxybenzylsulphi de),6-(4-hydroxy-3,5-di-t-butylanilino)-2,4-bis(octylthio)-1,3,5-t riazine,N,N′-hexamethylenebis(3,5-di-t-butyl-4-hydroxy-hydrocinnamide),3,5-di-t-butyl-4-hydroxy-benzyl-phosphate diester,bis(3-methyl-4-hydroxy-5-t-butylbenzyl)sulphide,3,9-bis[1,1-dimethyl-2-{β-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy}ethyl]-2,4,8,10-tetraoxaspiro[5,5]undecane,1,1,3-tris(2-methyl-4-hydroxy-5-t-butylphenyl)butane and1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benz ene; and

phenolic antioxidants with ester group such as alkyl3-(4-hydroxy-3,5-di-t-butylphenyl)propionate, alkyl3-(4-hydroxy-3-methyl-5-di-t-butylphenyl)propionate,tetrakis{3-(4-hydroxy-3,5-di-t-butylphenyl)propionyloxymethyl} methane,3-(4-hydroxy-3,5-di-t-butylphenyl)propionate glycerol monoester, esterof 3-(4-hydroxy-3,5-di-t-butylphenyl)propionic acid and glycerolmonooleyl ether, 3-(4-hydroxy-3,5-di-t-butylphenyl)propionate butyleneglycol diester, 3-(4-hydroxy-3,5-di-t-butylphenyl)propionatethiodiglycol diester,2,2-thio-{diethyl-bis-3-(3,5-di-t-butyl-4-hydroxyphenyl)}propi onate,bis{3,3′-bis-(4′-hydroxy-3′-t-butylphenyl)butyric acid} glycol ester.

The component (E) is preferably a phenolic antioxidant with ester groupbecause of an effect of lubricity improvement and a phenolic antioxidantwith one ester group is more preferred because of high solubility inbase oils, alkyl 3-(4-hydroxy-3,5-di-t-butylphenyl)propionate and alkyl3-(4-hydroxy-3-methyl-5-di-t-butylphenyl)propionate are still morepreferred and alkyl 3-(4-hydroxy-3,5-di-t-butylphenyl)propionate is themost preferred. The alkyl group in the alkyl moiety in alkyl3-(4-hydroxy-3,5-di-t-butylphenyl)propionate and alkyl3-(4-hydroxy-3-methyl-5-di-t-butylphenyl)propionate is preferably analkyl group having 4 to 22 carbon atoms because of high solubility inbase oils, an alkyl group having 6 to 18 carbon atoms is more preferred,an alkyl group having 7 to 12 carbon atoms is still more preferred, analkyl group having 7 to 9 carbon atoms is yet more preferred and abranched alkyl group having 7 to 9 carbon atoms is the most preferred.

When the content of the component (E) in the lubricating composition ofthe present invention is extremely low, an antioxidant effect is low,and when the content is extremely high, the performance improvementcommensurate with the added amount may not be obtained and decompositionof the component (A) may be promoted. Therefore, the content of thecomponent (E) is preferably 0.01% to 1% by mass, more preferably 0.15%to 0.95% by mass and the most preferably 0.2% to 0.9% by mass relativeto the whole amount of the lubricating composition. Lubricating oils forinternal combustion may contain, as an antioxidant, an amine antioxidantin some cases. However, the lubricating composition of the presentinvention preferably does not contain an amine antioxidant because theamine antioxidant may reduce the effect of friction reduction of thecomponent (A) by the component (B), and even if contained, the contentthereof is preferably 0.3% by mass or less, more preferably 0.1% by massor less and still more preferably 0.05% by mass or less relative to thewhole amount of the lubricating composition.

[Anti-Wear Agent]

Examples of the anti-wear agent include zinc dithiophosphates, alkylphosphate esters, aryl phosphate esters, alkyl thiophosphate esters andthe like. The lubricating composition of the present inventionpreferably contains, as a component (F), a zinc dithiophosphaterepresented by the following general formula (3) because of a highanti-wear effect and also an effect of lubricity improvement of thecomponent (A):

wherein R⁷ to R¹⁰ respectively represent an alkyl group having 3 to 14carbon atoms.

In the general formula (3), R⁷ to R¹⁰ respectively represent an alkylgroup having 3 to 14 carbon atoms. Examples of the alkyl group having 3to 14 carbon atoms include linear primary alkyl groups such as a propylgroup, a butyl group, a pentyl group, a hexyl group, a heptyl group, anoctyl group, a nonyl group, a decyl group, a dodecyl group, a tridecylgroup and a tetradecyl group; branched primary alkyl groups such as anisobutyl group, an isopentyl group, an isohexyl group, an isoheptylgroup, an isooctyl group, an isononyl group, an isodecyl group, anisododecyl group, an isotridecyl group, an isotetradecyl group, a2-methylpentyl group, a 2-ethylhexyl group, a 2-propylheptyl group, a2-butyloctyl group, a 2-pentylnonyl group and a 3, 7-dimethyloctylgroup; secondary alkyl groups such as an isopropyl group, a secondarybutyl group, a secondary pentyl group, a secondary hexyl group, asecondary heptyl group, a secondary octyl group, a secondary nonylgroup, a secondary decyl group, a secondary dodecyl group, a secondarytridecyl group, a secondary tetradecyl group and a 1,3-dimethylbutylgroup; tertiary alkyl groups such as a t-butyl group and a t-pentylgroup. R⁷ to R¹¹ are respectively preferably a secondary alkyl grouphaving 4 to 14 carbon atoms, more preferably a secondary alkyl grouphaving 4 to 10 carbon atoms and still more preferably a secondary alkylgroup having 4 to 8 carbon atoms because of lubricity improvement of thecomponent (A). Specifically, a 1-methylpropyl group and a1,3-dimethylpropyl group are preferred. R⁷ to R¹⁰ may be the same groupor a combination of different groups.

When the content of the component (F) is extremely low, an effect ofimprovement of an antioxidation effect may not be sufficient, and whenthe content is extremely high, the performance improvement commensuratewith the added amount may not be obtained and sludge may be generated.The content of the component (F) in terms of the phosphorus amountderived from the component (F) is preferably 0.001% to 3% by mass, morepreferably 0.005% to 2% by mass and the most preferably 0.01% to 1% bymass relative to the whole amount of the lubricating composition.

The lubricating composition of the present invention preferablycontains, as a component (G), an ashless friction regulator selectedfrom the group consisting of polyhydric alcohol fatty acid partialesters, (poly)glycerol alkyl ethers, alkyl alkanolamines, alkenylalkanolamines and fatty acid alkanolamides because friction may befurther decreased.

Examples of the polyhydric alcohol fatty acid partial ester includeglycerol monolaurate, glycerol dilaurate, glycerol monomyristate,glycerol dimyristate, glycerol monopalmitate, glycerol dipalmitate,glycerol monostearate, glycerol distearate, glycerol monooleate,glycerol dioleate, diglycerol monooleate, diglycerol dioleate,trimethylolpropane monooleate, trimethylolpropane dioleate and the like.

Examples of the (poly)glycerol alkyl ether include glyceryl laurylether, glyceryl myristyl ether, glyceryl palmityl ether, glycerylstearyl ether, glyceryl oleyl ether, diglyceryl oleyl ether, triglyceryloleyl ether and the like.

Examples of the alkyl alkanolamine include lauryl diethanolamine,myristyl diethanolamine, palmityl diethanolamine, stearyldiethanolamine, lauryl dipropanolamine, myristyl dipropanolamine,palmityl dipropanolamine, stearyl dipropanolamine and the like. Examplesof the alkenyl alkanolamine include oleyl diethanolamine, oleyldipropanolamine and the like.

Examples of the fatty acid alkanolamide include fatty acidmonoethanolamides such as lauric acid monoethanolamide, myristic acidmonoethanolamide, palmitic acid monoethanolamide, stearic acidmonoethanolamide and oleic acid monoethanolamide; fatty aciddiethanolamides such as lauric acid diethanolamide, myristic aciddiethanolamide, palmitic acid diethanolamide, stearic aciddiethanolamide and oleic acid diethanolamide; fatty acidN-methylethanolamides such as lauric acid N-methylethanolamide, myristicacid N-methylethanolamide, palmitic acid N-methylethanolamide, stearicacid N-methylethanolamide and oleic acid N-methylethanolamide.

The component (G) is preferably a polyhydric alcohol fatty acid partialester and a (poly)glycerol alkyl ether, more preferably a polyhydricalcohol fatty acid partial ester, still more preferably a glycerolmono-fatty acid ester and the most preferably glycerol monooleate.

When the content of the component (G) is extremely low, sufficienteffect is not obtained, and when the content is extremely high, aperformance improvement commensurate with the added amount may not beobtained. The content of the component (G) is preferably 0.01% to 5% bymass, more preferably 0.05% to 2% by mass and still more preferably 0.1%to 1% by mass relative to the whole amount of the lubricatingcomposition.

The lubricating composition of the present invention may further containother lubricant additives that are generally used for lubricating oil.Examples of the lubricant additives include (H1) a phosphorus-basedanti-wear agent or phosphorus-based antioxidant, (H2) a sulphur-basedextreme pressure agent, (H3) a sulphur-based antioxidant, (H4) athiophosphate-based extreme pressure agent, (H5) a rust preventingagent, (H6) a viscosity index improver, (H7) a metal deactivator, (H8) adefoaming agent, (H9) a solid lubricant and the like.

Examples of (H1) the phosphorus-based anti-wear agent orphosphorus-based antioxidant include organic phosphines, organicphosphine oxides, organic phosphinites, organic phosphonites, organicphosphinates, organic phosphites, organic phosphonates, organicphosphates, organic phosphoroamidates and the like.

Examples of (H2) the sulphur-based extreme pressure agent includesulphurized oil, sulphurized mineral oil, organic mono- orpoly-sulphides, sulphurized polyolefins, 1,3,4-thiadiazole derivatives,thiuram disulphides, dithiocarbamate esters and the like.

Examples of (H3) the sulphur-based antioxidant include thiodipropionateesters, thiobis(phenol) compounds, polyhydric alcohol esters ofalkylthiopropionic acids, 2-mercaptobenzimidazole, dilauryl sulphide,amyl thioglycolate and the like.

Examples of (H4) the thiophosphate-based extreme pressure agent includeorganic trithiophosphites, organic thiophosphates and the like.

The amounts of the components (H1) to (H4) added are preferably about0.01% to 2% by mass, respectively, relative to the lubricatingcomposition of the present invention. When the lubricating compositionof the present invention is used as an engine oil, it is preferable touse the components in such a range that the total phosphorus content inthe lubricating composition does not exceed 1000 ppm by mass and thetotal sulphur content does not exceed 5000 ppm by mass because exhaustgas purification catalysts may be toxified.

Examples of (H5) the rust preventing agent include oxidised paraffin waxcalcium salts, oxidised paraffin wax magnesium salts, alkali metalsalts, alkaline earth metal salts and amine salts of tallow fatty acids,alkenyl succinic esters and alkenyl succinic half-esters (molecularweight of the alkenyl group is about 100 to 300), sorbitan monoesters,pentaerythritol monoesters, glycerol monoesters, nonylphenolethoxylates, lanolin fatty acid esters, lanolin fatty acid calcium saltsand the like. The amount of the component (H5) added is preferably about0.1% to 15% by mass relative to the whole amount of the lubricatingcomposition, which range allows sufficient exhibition of a rustpreventing effect.

Examples of the component (H6), viscosity index improver, includepoly(C1-18)alkyl methacrylates, (C1-18)alkylacrylate/(C1-18)alkylmethacrylate copolymers, diethylaminoethylmethacrylate/(C1-18)alkyl methacrylate copolymers,ethylene/(C1-18)alkylmethacrylate copolymers, polyisobutylenes,polyalkylstyrenes, ethylene/propylene copolymers, styrene/maleic estercopolymers, styrene/maleamide copolymers, hydrogenated styrene/butadienecopolymers, hydrogenated styrene/isoprene copolymers and the like. Theaverage molecular weight is about 10,000 to 1,500,000. The amount of thecomponent (H6) added is preferably about 0.1% to 20% by mass relative tothe whole amount of the lubricating composition.

Examples of the component (H7), metal deactivator, includeN,N′-salicylidene-1,2-propanediamine, alizarin, tetraalkyl thiuramdisulphides, benzotriazole, benzimidazole, 2-alkyl dithiobenzimidazoles,2-alkyl dithiobenzothiazoles,2-(N,N-dialkylthiocarbamoyl)benzothiazoles,2,5-bis(alkyldithio)-1,3,4-thiadiazoles,2,5-bis(N,N-dialkylthiocarbamoyl)-1,3,4-thiadiazoles and the like. Theamount of the component (H7) added is preferably about 0.01% to 5% bymass relative to the lubricating composition.

Examples of the component (H8), defoaming agent, includepolydimethylsilicone, trifluoropropylmethylsilicone, colloidal silica,polyalkyl acrylates, polyalkyl methacrylates, alcoholethoxylates/propoxylates, fatty acid ethoxylates/propoxylates, sorbitanpartial fatty acid esters and the like. The amount of the component (H8)added is preferably about 1 to 1000 ppm by mass relative to the wholeamount of the lubricating composition.

Examples of the component (H9), solid lubricant, include graphite,molybdenum disulphide, polytetrafluoroethylene, fatty acid alkalineearth metal salts, mica, cadmium dichloride, cadmium diiodide, calciumfluoride, lead iodide, lead oxide, titanium carbide, titanium nitride,aluminium silicate, antimony oxide, cerium fluoride, polyethylene,diamond powder, silicon nitride, boron nitride, carbon fluoride,melamine isocyanurate and the like. The amount of the component (H9)added is preferably about 0.005% to 2% by mass relative to the wholeamount of the lubricating composition.

Each of the components (H1) to (H9) added may appropriately be one ormore compounds.

The lubricating composition of the present invention may be used forlubrication of various applications. For example, engine oils such asgasoline engine oil and diesel engine oil, industrial lubricating oil,turbine oil, machine oil, bearing oil, compressor oil, hydraulic oil,operating oil, internal combustion oil, refrigerant oil, gear oil,automatic transmission fluid (ATF), continuously variable transmissionfluid (CVTF), transaxle fluid, metal processing oil and the like may bementioned. Alternatively, the lubricating composition may be added andused in various greases for slide bearings, roller bearings, gearwheels, universal joints, torque limiters, automobile constant velocityjoints (CVJs), ball joints, wheel bearings, constant velocity gears,transmission gears and the like.

EXAMPLES

The present invention is hereinafter more specifically described by wayof the Examples. In the Examples, “%” is based on the mass unlessotherwise stated.

With the following compounds and base oils, lubricating compositions ofExamples 1 to 10 and Comparative Examples 1 to 5 having the compositionsindicated in Table 1 were prepared. The values of the compositionsindicated in the table are in parts by mass of compounds when the wholeamount of the lubricating composition is regarded as 100 parts by mass.

(A1) Compound of general formula (1), wherein R¹ and R² are respectivelya 2-ethylhexyl group, R³ and R⁴ are respectively a branched tridecylgroup, X¹ and X² are respectively a sulphur atom and X³ and X⁴ arerespectively an oxygen atom (Mo content: 18.1%)

-   (A2) Compound of general formula (1), wherein R⁴ to R⁴ are    respectively a 2-ethylhexyl group, X⁴ and X² are respectively a    sulphur atom and X³ and X⁴ are respectively an oxygen atom (Mo    content: 20.7%)-   (B1) Compound of general formula (2), wherein R⁵ and R⁶ are    respectively a 2-ethylhexyl group-   (B2) Compound of general formula (2), wherein R⁵ and R⁶ are    respectively a branched tridecyl group-   (C1) Calcium salicylate (Ca content: 10%, TBN: 280 mgKOH/g)-   (C2) Boron-modified calcium salicylate (Ca content: 10%, boron    content: 0.5%, TBN: 275 mgKOH/g)-   (C3) Magnesium salicylate (Mg content: 6.0%, TBN: 280 mgKOH/g)-   (C′1) Calcium sulphonate (Ca content: 11.4%, TBN: 300 mgKOH/g)-   (D1) Bis(polyalkenyl succinimide)-   (D2) Borated alkenyl succinimide (boron content: 0.34%)-   (D′1) Mannich base dispersant-   (E1) Phenolic antioxidant with ester group indicated below:

wherein R¹¹ is a branched alkyl group having 7 to 9 carbon atoms

(F1) Compound of general formula (3), wherein R⁷ to R¹⁰ are respectivelya 1-methylpropyl group or a 1,3-dimethylbutyl group

-   (Base oil) Mineral oil-based oil with high VI having a kinetic    viscosity at 40° C. of 18.3 mm²/s and a viscosity index of 126

The lubricating compositions of Examples 1 to 10 and ComparativeExamples 1 to 5 were measured for coefficient of friction andcorrosiveness to copper plates according to the methods indicated below.The results are indicated in Table 1.

[Method for Determining Coefficient of Friction]

-   Tester used: SRV tester (produced by Optimol Instruments-   Prüftechnik GmbH, model: type 3)    Evaluation conditions:    -   The coefficient of friction is measured under line contact        conditions of a cylinder on a plate.    -   Load: 200 N    -   Temperature: 80° C.    -   Measurement time: 15 minutes    -   Stroke: 1 mm    -   Upper cylinder: ϕ15×22 mm (material: SUJ-2)    -   Lower plate: ϕ24×6.85 mm (material: SUJ-2)-   Evaluation method: The average coefficient of friction between 5 to    15 minutes is regarded as the coefficient of friction obtained by    the present test. A lower coefficient of friction indicates better    lubricity.

[Test Method of Corrosiveness to Copper Plates]

-   Test method: according to JIS K2513 (Petroleum    products-Corrosiveness to copper-Copper strip test)-   Test temperature: 100° C.-   Test period: 3 hours-   Evaluation method: The extent of corrosion is judged by comparing    the discoloration of copper plates with the corrosion standard of    the copper plate according to JIS K2513. The smaller number means    less corrosion, and for the same numbers, corrosion is from low to    high in the order of a→b→c. Systematic corrosion according to the    corrosion standard of the copper plate is indicated in Table 1.

Examples 1 2 3 4 5 6 7 8 A1 0.39 0.39 0.39 0.39 0.39 — 0.39 0.39 A2 — —— — — 0.34 — — B1 0.005 0.010 0.013 0.005 — 0.010 — 0.005 B2 — — — 0.0050.010 — 0.010 0.005 C1 2.8 2.8 2.8 2.8 2.8 2.8 — — C2 — — — — — — 2.8 —C′1 — — — — — — — 2.8 D1 4 4 4 4 4 4 4 4 D2 — — — — — — — — D′1 — — — —— — — — E1 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8 F1 1 1 1 1 1 1 1 1 Base oilBalance Balance Balance Balance Balance Balance Balance Balance Mocontent ppm 700 700 700 700 700 700 700 700 100 * (amine/Mo) 7.1 14.218.6 14.2 14.2 14.2 14.2 14.2 Friction coefficient 0.063 0.062 0.0610.062 0.061 0.062 0.062 0.060 Copper plate corrosiveness 1a 1a 1b 1a 1a1a 1a 1a Examples Comparative Examples 9 10 1 2 3 4 5 A1 0.39 0.39 0.390.39 — — — A2 — — — — 0.34 0.34 — B1 0.010 0.005 — 0.012 — — 0.010 B2 —0.005 — 0.012 — 0.025 — C1 2.8 2.8 2.8 2.8 2.8 2.8 2.8 C2 — — — — — — —C′1 — — — — — — — D1 — — 4 4 4 4 4 D2 4 — — — — — — D′1 — 4 — — — — — E10.8 0.8 0.8 0.8 0.8 0.8 0.8 F1 1 1 1 1 1 1 1 Base oil Balance BalanceBalance Balance Balance Balance Balance Mo content ppm 700 700 700 700700 700 0 100 * (amine/Mo) 14.2 14.2 — 34.2 — 35.5 — Frictioncoefficient 0.062 0.064 0.068 0.060 0.067 0.061 0.121 Copper platecorrosiveness 1a 1a 1a 2d 1a 2d 1a

1. A lubricant additive composition comprising, as a component (A), anorganic molybdenum compound represented by the following general formula(1), and as a component (B), an amine compound represented by thefollowing general formula (2), wherein content of the component (B) is 1to 20 parts by mass relative to 100 parts by mass of molybdenum atoms ofthe component (A):

wherein R¹ to R⁴ respectively represent an alkyl group having 1 to 18carbon atoms, and X¹ to X⁴ respectively represent an oxygen atom or asulphur atom;

wherein R⁵ and R⁶ respectively represent an alkyl group having 1 to 18carbon atoms or an alkenyl group having 2 to 18 carbon atoms.
 2. Alubricating composition comprising a base oil, and the lubricantadditive composition according to claim
 1. 3. The lubricatingcomposition according to claim 2, further comprising, as a component(C), an alkaline earth metal salicylate.
 4. The lubricating compositionaccording to claim 2, further comprising, as a component (D), an alkenylsuccinimide dispersant.
 5. The lubricating composition according toclaim 2, further comprising, as a component (E), a phenolic antioxidant.6. The lubricating composition according to claim 2, further comprising,as a component (F), a zinc dithiophosphate represented by the followinggeneral formula (3):

wherein R⁷ to R¹⁰ respectively represent an alkyl group having 3 to 14carbon atoms.
 7. The lubricating composition according to claim 2,further comprising, as a component (G), at least one ashless frictionregulator selected from the group consisting of polyhydric alcohol fattyacid partial esters, (poly)glycerol alkyl ethers, alkyl alkanolamines,alkenyl alkanolamines and fatty acid alkanolamides.
 8. An engine oilcomposition consisting of the lubricating composition according toclaim
 1. 9. A method for suppressing corrosion of a copper component ofa machine and improving lubrication ability by adding, to a base oilused for a lubricating composition, an organic molybdenum compoundrepresented by the following general formula (1) and an amine compoundrepresented by the following general formula (2), wherein the aminecompound is added at 1 to 20 parts by mass relative to 100 parts by massof molybdenum atoms of the organic molybdenum compound:

wherein R¹ to R⁴ respectively represent an alkyl group having 1 to 18carbon atoms, and X¹ to X⁴ respectively represent an oxygen atom or asulphur atom;

wherein R⁵ and R⁶ respectively represent an alkyl group having 1 to 18carbon atoms or an alkenyl group having 2 to 18 carbon atoms.